Python's OOP-oriented object-based programming basics

O bjects

Sorts of program Languages

Machine orinted

Machine instructions

Assembly

Procedure orinted

Follow steps and branch processing

C

Object orinted

Multi-person, multi-departmental writing

C + + Java Python

• Everything in Python, object-oriented, very thorough.

• Objects are encapsulated in data and operations

• Objects are independent, but objects can interact with each other

• At present, OOP is the closest programming paradigm to human cognition.

Oop

Description Data--property

Action--method

Class

Collection of profiles

There are no functions in the class, called methods.

Instance Object

Three elements of OOP:

1. Package:

Assembled and closed.

Data is hidden.

2. Inheritance:

Multiple multiplexing

Multiple inheritance less modification, OCP (open-closed Principle)

3, polymorphic:

Dynamic binding. Python almost doesn't exist

Python's class

class MyClass:

"" " A Example Class " ""

    ' abc '   # Class Property

    foo ( self ):  foo is method object

Print(self. x) , do not swap, pass the instance of the class itself as a method parameter

Print (MyClass)

Print (MyClass. __name__ )

Print (myclass.x)

Print ((myclass.foo))

<class ' __main__. MyClass ' >

MyClass

Abc

<function Myclass.foo at 0x00000000011cb840>

‘.’ It was used to find members.

. __dict__ you can get the dict that contains all the properties of MyClass, including the one we defined

X variable

__doc__: "" "A Example Class" ""

Foo method

and a default __module__:__main__.

__init__ Methods and other properties

Class objects and Class properties

• Class Object , define a class that is a class object type class

• properties of the class , the variables and methods in the definition are the properties of the class. All belong to the identifier of the class

• class Variables , in the example above, X is a variable of class MYCLASSD

Foo is a Methond method object, not a normal fucntion, must have at least one argument, and the first argument must be self.

Self refers to the current instance itself

mycls = MyClass () # Instantiate, Initialize

Print (Mycls.foo ()))

Print (mycls.x)

Print (Mycls.foo)

Abc

None

Abc

<bound method Myclass.foo of <__main__. MyClass Object at 0x00000000011e57f0>>

Class

Print (MyClass)

• Instantiation of

A = MyClass ()

After the class object is added (), the instantiation method of the calling class is invoked to complete the instantiation.

When the Python class is instantiated, the __init__ method is called automatically, and the first argument must be left to self.

def __new__ instantiation

• __init__ method

__init__ (self), initialization method, also called constructor, constructor method,

has been constructed to complete

Can only return none,

• Instance

1. Object after the class instantiation is an instance object

2. An instance variable is each instance of its own variable, a class variable is a variable of a class, and is a property and method shared by all instances of the class.

3. Class properties are stored in the __dict__ of the class, the instance properties are stored in the-__dict__ of the instance, and if the properties of the class are accessed from the instance, the owning class needs to be found with __class__.

__qualname__

Class type instances have qualified name __qualname__, not equal to name

__dict__ Property Collection

Lookup Order of Instance properties

The object operation of the function is the same

First look at your own dict, and then through the property __class__ find their own class and then go to the class of dict find.

Decorate a class

Call class with __xxxx__

• Is the class is everyone's.

• If you don't have a reference, use @staticmethod

Def STATICMTD ():

Print (' static ')

Access control public Protect private

Private property

_person__age can be found in the __dict__ of an instance because the interpreter is renamed

Protect Property

_name is the developer's agreement, do not change

Private method, similar to private variables

In the __dict__ of the class can be found

This article is from the "Python" blog, so be sure to keep this source http://13320196.blog.51cto.com/13310196/1979407

Python's OOP-oriented object-based programming basics